Rear Admiral Yu Manjiang, commander of China's navy, said the sea was a natural choice for the drill as the two countries have already held exercises in China's other waters.

“Some people and countries are pointing fingers at this (joint drill), but this is not necessary at all," he said, adding that the drill does not target a third party.

Last year, the two countries held joint military drills in the Sea of Japan and the Mediterranean, but this was the first time they held drills in the disputed sea.

Beijing claims almost all of the South China Sea, which is also contested in part by Taiwan, Brunei, Vietnam, Malaysia and the Philippines. The waters are believed to be rich in oil and gas.

Earlier in July, the Hague-based Permanent Court of Arbitration ruled that China’s claims to sovereignty over the disputed areas in the sea or its resources “had no legal basis” in a case brought by the Philippines.

China, however, rejected the verdict, arguing that the tribunal has no jurisdiction over the issue.

The sea has so far become a source of tensions between China, the US, and some other regional countries, which are seeking control of trade routes and mineral deposits there.